??? fossil

[drbush]

Hi friends ,can you help me with this ,I went to Aruma formation area (Cretaceous) to the north of Riyadh and found this small fossil , it is thin ,half a circle , 4 mm wide and 4 cm long , it was a surface find . What sp. could it be? 

[Rockwood]

It's a bit unusual, but I think the cretaceous may have seen crinoids with stalks like this.

[JamieLynn]

I have found cretaceous crinoid stalks (from Texas, not Saudi Arabia) and to me, they don't really look similar. I think this might be the top edge of one of the rudist species, perhaps Radiolites

 

 

This is cretaceous crinoid Isocrinus

[Rockwood]

Those rudists are a sneaky bunch. 

[FranzBernhard]

@drbush, how does it look like in side view/cross section? This would be critical observation!

Franz Bernhard

[Mark Kmiecik]

I'm seeing irregularities that preclude crinoid stem. I'm in the rudist camp here.

[drbush]

The cross section of the stone is thin 3-4 mm, flat layer. I do not have the full length 

[Rockwood]

4 minutes ago, drbush said:

The cross section of the stone is thin 3-4 mm, flat layer. I do not have the full length 

But was the fossil as flat, or has it been sectioned is what we need to know.

[drbush]

flat

[Rockwood]

5 hours ago, drbush said:

flat

I think that would tend to favor it being the rim of a rudist seen in sectioned view.